Apparatus for identifying opposite sides of a moving strip



W. E. COLEMAN APPARATUS FOR IDENTIFYING OPPOSITE Feb. 1, 1955 SIDES OF A MOVING STRIP Filed 001.. 22, 1953 Svh vm 1N VEN TOR. W/L L MM E. COLEMAN,

flow/ his Attorney from the connection between power source 62 and contacts 580. If the top side of thestrip in the line is smooth and the bottom side rough the potential across resistor 38 will be appreciably greater than that across resistor 40 and the plate potential of tube 42 will be appreciably lower than that of tube 44. Under these conditions the grid of gas tube 54 will be appreciably lower in potential than its cathode and the tube will not conduct. Thus the relay contacts 580 will remain closed. If the coating thickness on the top of the strip is greater than or equal to that of the coating thickness on the bottom of the strip or if thecoating thickness on either side is not within the limits set on the meters 24 and;26 at least one of the contacts 64 and 66 will be open and the relay coil 60 will not be energized. Thus the contact 60C will be in position shown and the lamp 84 will be lit indicating improper operation. The operator will then stop the line.

On the other hand if the correct coating is being applied to both sides of the strip a circuit will be completed through the coil 60, thus moving its contact arm to complete a circuit through the lamp 82. When the lamp 82 is lit it indicatesthat the system is operating satisfactorily. Although a gas tube operated relay is described it is theoretically possible to operate the relay directly from the potential developed by the photocells or directly from the potential developed between the plates 42p and 44p. However, it is desirable to have the additional sensitivity provided by the amplification of the tubes 42 and 44 and the sharp control point provided by tube 54.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. In a processing line for applying a different thickness of coating material to opposite sides of a strip having one relatively rough and one relatively smooth side, the combination therewith of apparatus for determining whether the proper coatings are being applied to the proper surfaces of a strip passing therethrough; said apparatus comprising a first coating thickness meter for indicating the thickness of coating applied to the first side of the strip, a second coating thickness meter for indicating the thickness of coating applied to the second side of the strip, a first switch associated with said first meter, said first switch being closed when a predetermined coating is being applied to the first side of the strip, a second switch associated with said sec-nd meter, said second switch being closed when a predetermined coating is being applied l to the second side of the strip, means for determining the relative roughness of opposite surfaces of the strip, a third switch, means operable by said last named means for closing said third switch when the relative roughness of opposite surfaces of the strip is that desired, a circuit 7 including said three switches connected in series, and means operable by the closing of said three switches for indicating that the proper coatings are being applied to the proper surfaces of the strip.

2. In a processing line for applying a different thickness of coating material to opposite sides of a strip having one relatively rough and one relatively smooth side, the combination therewith of apparatus for determining whether the proper coatings are being applied to the proper surfaces of a strip passing therethrough; said apparatus comprising a first coating thickness meter for indicating the thickness of coating applied to the first side of the strip, a second coating thickness meter for indicating the thickness of coating applied to the second side of the strip, a first switch associated with said first meter, said first switch being closed when a predetermined coating is being applied to the first side of the strip, a second switch associated with said second meter, said second switch being closed when a predetermined coating is being applied to the second side of the strip, two reflectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means for obtaining a voltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means connecting said voltage impulses in opposed relationship, a third switch, means operable by said last named means for closing said third switch when the relative roughness of opposite'surfaces of the strip is that desired,

a circuit including said three switches connected in series, and means operable by the closing of said three switches for indicating that the proper coatings are being applied to the proper surfaces of the strip.

3. In a processing line for applying a diiferent thickness of coating material to opposite sides of a strip having one relatively rough and one relatively smooth side, the combination therewith of apparatus for determining whether the proper coatings are being applied to the proper surfaces of a strip passing therethrough; said apparatus comprising a first coating thickness meter for indicating the thickness of coating applied to the first side of the strip, a second coating thickness meter for indicating the thickness of coating applied to the second side of the strip, a first switch associated with said first meter, said first switch being closed when a predetermined coating is being applied to the first side of the strip, a second switch associated with said second meter, said second switch being closed when a predetermined coating is being applied to the second side of the strip, two reflectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means for obtaining a voltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means connecting said voltage impulses in opposed relationship, a third switch, means operable by said last named means for closing said third switch when the relative roughness of opposite surfaces of the strip is that desired, a relay coil, a power source, said relay coil, power source and switches being connected in series, contacts operable by said relay coil, and signal means connected in series with said contacts for indicating whether the proper coatings are being applied to the proper surfaces of the strip.

4. In a processing line for applying a dififerent thickness of coating material to opposite sides of a strip having one relatively rough and one relatively smooth side, the combination therewith of apparatus for determining whether the proper coatings are being applied to the proper surfaces of a strip passing therethrough; said apparatus comprising a first coating thickness meter for indicating the thickness of coating applied to the first side of the strip, a second coating thickness meter for indicating the thickness of coating applied to the second side of the strip, a first switch associated with said first meter, said first switch being closed when a predetermined coating is being applied to the first side of the strip, a second switch associated with said sec-0nd meter, said second switch being closed when a predetermined coating is being applied to the second side of the strip, two refiectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means for obtaining avoltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means for amplifying each of the voltage impulses, means connecting said amplifying means in opposed relationship, a relay coil having a normally closed contact, a power source and an electronic tube connected in series with said relay coil, means for impressing the output of said last named means on the grid of said electronic tube, said electronic tube being connected to conduct when no voltage is applied to its grid, a circuit including said switches and relay contacts connected in series, and means operable by the closing of said switches and relay contacts for indicating that the proper coatings are being applied to the proper surfaces of the strip.

5. In a processing line for applying a different thickness of coating material to opposite sides of a strip having one relatively rough and one relatively smooth side, the combination therewith of apparatus for determining whether the proper coatings are being applied to the proper surfaces of a strip passing therethrough; said apparatus comprising a first coating thickness meter for indicating the thickness of coating applied to the first side of the strip, a second coating thickness meter for indicating the thickness of coating applied to the second side of the strip, a first switch associated with said first meter, said first switch being closed when a predetermined coating is being applied to the first side of the strip, a sec-0nd switch associated with said second meter, said second switch being closed when a predetermined coating is being applied to the second side of the strip, two

reflectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means for obtaining a voltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means for amplifying each of the voltage impulses, means connecting said amplifying means in opposed relationship, a relay coil having a normally closed contact, a power source and an electronic tube connected in series with said relay coil, means for impressing the output of said last named means on the grid of said electronic tube, said electronic tube being connected to conduct when no voltage is applied to its grid, a second relay coil, a power source, said second relay coil, power source, switches and relay contact being connected in series, contacts operable by said second relay coil, and signal means connected in series with said last named contacts for indicating whether the proper coatings are being applied to the proper surfaces of the strip.

6. Apparatus for indicating the relative roughness of opposite surfaces of a moving strip having one relatively rough and one relatively smooth side comprising two reflectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means or obtaining a voltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means connecting said voltage impulses in opposed relationship, a

switch, means operable by said last named means for closing said switch when the relative roughness of opposite surfaces of the strip is that desired, and means operable by said switch for indicating that the relative roughness of the opposite surfaces of the strip is that desired.

7. Apparatus for indicating the relative roughness of opposite surfaces of a moving strip having one relatively rough and one relatively smooth side comprising two reflectometers one on each side of the strip, each of said reflectometers including a photosensitive device, means for obtaining a voltage impulse proportional to the output of the first of said photosensitive devices, means for obtaining a voltage impulse proportional to the output of the second of said photosensitive devices, means for amplifying each of the voltage impulses, means connecting said amplifying means in opposed relationship, a relay coil having a normally closed contact, a power source and an electronic tube connected in series with said relay coil, means for impressing the output of said last named means on the grid of said electronic tube, and means operable by said switch for indicating that the relative roughness of the opposite surfaces of the strip is that desired.

References Cited in the file of this patent UNITED STATES PATENTS 

